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HOW TO: IMRC Removal and Repair

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dsi imrc
231K views 191 replies 86 participants last post by  AussieRigby 
#1 ·
First off, credit for this idea goes to an older thread which now seems to be gone. I'm just going into slightly more detail.


This problem is very common, and I suspect 80% of SVT owners need not replace the IMRC but simply clean the internal contacts.


So, do you have this problem? If you answer "no" to the following, it is 90% likely this procedure will work for you:

1) Is my cable broken?
2) Is my lever broken?

What you need:

1/4in ratchet with 8mm & 10mm sockets
Phillips screw driver #1 & #2
Soldering Iron
Thermal paste
RTV



Ok, lets begin.


First, remove the drivers side headlamp, battery, battery tray, and airbox/uper half of CAI/SRI:






You see that the IMRC is located behind the headlamp.

Now, before unbolting the IMRC box, disconnect the cable from the lever. This is done by (with one hand) roatating the lever towards you, while grasping the end of the cable and sliding it off of the post.







Now, unbolt the box and remove it while snaking the cable out along the path shown.



Ok, the hard part is done [thumb]

Next, take the IMRC to your bench to begin disassembly.



First, remove screws securing cover. Then using a straight razor blade cut around the seam to free the RTV.



Now that the unit is open, remove the screws as shown, and desolder the power wires and connector pins.



Remove PCB, and this is what you have.






At this point you will notice, there is not much to this box. Notice the gears are made of metal, thus the odds they will ever strip is very slim. The electrical circuit is very simple as well, and failure of these components under normal operation is slim to none. The motor is nothing more than a glorified coil, and under normal operation coils are basically indestructable.

Leaving us with the true weak point of this unit... the contact [smackbum] Which is the copper strip with a nickel plated contact shown in the above picture.

Now, to remedy the dreaded P1518, we must burnish (clean) said contact.

Notice the grey color. This is not very condusive to conduction. [idea]






Using a piece of fine grit sand paper (paper), or a fine nail file (file), press down gently on the copper strip (DO NOT BEND COPPER STRIP),

Insert paper/file, release copper strip and pull paper/file out. DO NOT MOVE BACK AND FORTH, SIMPLY PULL.

Repeat 3-5 times, and marvel at your new looking contact.




Now, before you reasemble the box, make sure your FET has enough remaining thermal grease to dissapate heat properly... In my case, I wiped it away and used thermally conductive gap pad.

Add thermal grease if you need to.








Now reattach the PCB the reverse of removal.

Using standard RTV, run a bead around the edge and screw the cover back on.




Bolt up the box to its bracket and run the cable along the same path you took it out of. BE SURE TO RUN THE CABLE INTO THE GROOVE BEHIND THE BATTERY TRAY, SO THAT WHEN YOU PUT THE TRAY BACK IN YOU DO NOT SMASH THE CABLE.

Hook up the cable end to the lever post by rotating the lever towards you and sliding the groove of the cable end on to the post.

Replace airbox/upper half CAI/SRI, battery tray, and battery.

Hook up battery... Start car... and enjoy your engine codeless dash [wiggle]

I'm sure I forgot something, I will edit as I remember things or get suggestions from other members.
 
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#62 ·
Nice guide! I was following it but unfortunately got stuck. I was able to remove the headlight, upper portion of the air filter box and even get the end of the cable from the lever but got stuck once I realized that I couldn't remove the cable from the bracket next to the lever. It appears it's supposed to slip off the side but I couldn't get it to slip off. I tried spinning it, thinking maybe I had to unscrew something but that didn't work. I also just trying to slip it off using light force but it didn't seem to budge and I didn't want to break anything.

Any tips?
 
#66 ·
I found the removal of the wire clip is the worst part of the repair.
I forced it out and thought I broke the cable but I was lucky. The wire end clip is made of nylon and didn't break:

This is how the cable end look:


I found the right way to remove it, is by either:
1. you can push the nylon head in -OR-
2. rotate the cable until the slot head aligned with the holder bracket and you should be able to slip off through the side.


Good luck.
Tat
2003 SVT-Focus
 
#64 ·
Is there something I need to do to loosen it up? I may try spraying some WD40 on it and letting that sit for a bit to see if it helps. I can twist the cable within the bracket so I know it's not stuck that way. When I tried pulled on it I could tell the entirety of the intake manifold was moving around a bit so I didn't want to force it. Thanks for the insight!
 
#69 ·
I managed to get my IMRC box out and take it apart. I didn't trust my soldering skills to completely disassemble it but I was still able to sneak the sand paper into the crucial contact spot. After cleaning and reassembly, my CEL is gone (or at least has been since Sunday.) The exhaust note is back to normal, my torque has doubled and I finally love my SVT again. Thanks again for everyone's help! [pray]
 
#70 ·
Ok, so I wanted to wait a little while before posting results, but I finally broke down (not literally) and replaced my IMRC. I just bought a new one from Tousley and installed it myself. Pretty easy job, only removed the airbox to disconnect the cable, then went in from underneath to swap it out. I reset the CEL and so far, after about 600 miles, the light has not returned. I think my MPGs are better, but it's kinda hard to tell since I ran in an autocross last weekend... I'll keep you posted.

So if anyone wants a slightly bad IMRC to try to take apart and fix, I've got one I'll sell pretty cheap. That way you can try the fix without disabling your car in the process.
 
#75 ·
Since we cant find a replacement spring, I went to the local auto parts and found a carb return spring with a long shapeable end. The other end is round and slips over the screw head (we installed in the old DSI lever/clip) to hold the cable in place. I found a convienient place on the firewall to secure the long end so it holds the manifold butterflies shut and then bent and cut off the excess.
So far it works great and was under $2.00..
 
#77 ·
Does anyone know when IMRC'n is suppose to move, my move at 6200rpm which I think is way too high. Does anyone know when the IMRC should move, or maybe someone can go out and look at his own car? (Just stand beside and look at the DSI clip while someone else hit the trottle)

I get error code P1518, but are not noticing anything wrong except that IMRC'n moving at such a high rpm ...

Thanks!
 
#83 ·
i didnt unsolder mine. just wrapped a thin screwdriver with some sand paper,zipped tied it to keep it tight, got it in there, and cleaned up the contacts. been good ever since.
 
#86 ·
There's another write up floating around that explains that because of the mechanical action the solder can crack on the two biggest contacts on the board. When I did mine I cleaned the contact and laid some fresh solder on them to be safe.

I actually enjoy soldering, I've been a soldering fool on this Focus. haha
 
#87 ·
i don't really mind it. i have been using a lot of solder and electrical connects here lately.
i've light up my floor boards, cup holders, entire hatch area and hardwired a phone charger to a couple holder.
burned the f### out of my hand too.
 
#92 ·
I wanted to clarify how to remove the wire from the mount since I've been getting very PO'd trying to figure it out.

Identify the cable as it runs between the battery box and the engine.

Reach down with your left hand and grab it.

Turn the cable so that the two tabs that need to be compressed are sitting at 12 and 6, straight up and straight down.

Take a flat head screw driver and press down on the top tab while gently pulling back on the cable. ( Back meaning pull it towards the front of the car.)

Depressing the one tab allowed it to slip out partially and the bottom tab just folded all the way flat and the cable pulled out.

Honestly I could see this breaking the bottom tab on some brittle plastic so If you can fit some flat needle nose, regular needle nose will not fit, to compress both sides, that should work even better.
 
#94 ·
My IMRC has been broken since last fall; I pulled it out in late November and have been driving around with it removed up until yesterday, 8/4/2012. The only reason I replaced it is because I was sick of looking at the Check Engine light on the dash. But I wanted to comment that since I replaced it yesterday, and have put over 100 miles highway miles on it and another 20-30 city miles, I don't notice any difference, other than the Check Engine light isn't on anymore. It doesn't feel anymore responsive at high or low speeds or rpms. Hopefully I notice my mpg increase, because I did notice a dip of about 4mpg when it stopped working. We will see. Did anyone else notice little to no difference when there IMRC wasn't functioning?
 
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